Enzymatic hydrolysis of starch in water-immiscible organic solvent,two-phase systems |
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Authors: | Takashi Morita Isao Karube |
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Institution: | (1) Akebono Brake Research & Development Center Ltd., Higashi Hanyu, Saitama Pref., Japan;(2) Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153 Tokyo, Japan |
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Abstract: | Enzyme-catalyzed hydrolyzations of starch by α-amylase have been studied in various two-phase systems, consisting of water
and a water-immiscible organic solvent. The hydrolytic conversion of soluble starch to malto-oligosaccharides by α-amylase
was greatly accelerated in 10% (v/v) water content of water-dodecane two-phase systems. However, a rapid inactivation of the
enzyme has been observed in these systems. Addition of surfactant to these systems, such as polyoxyethylene (20) sorbitan monopalmitate (Tween 60) or bis(2-ethylhexyl) sodium sulfosuccinate (AOT), was effective for the enzyme stability.
Effects of enzyme immobilization on the stability of α-amylase, using Ca-alginate and chitosan beads, also have been studied.
The stability of immobilized enzyme was clearly enhanced in a 5–10% (v/v) water content two-phase system, whereas the free
enzyme was inactivated within 41 h, remaining at a relative activity of 47–76% after 41 h of treatment. Furthermore, scanning
electron micrographs (SEM) were taken to observe the effect of the two-phase system on the hydrolysis of starch. Potato starch
granules have been extremely swelled and burst out in the stirred 10% (v/v) water content system, which did not contain enzymes. |
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Keywords: | α -Amylase starches enzymatic hydrolysis in water-immiscible organic media surfactants immobilization |
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